The invention relates to an air feeding arrangement for a piston engine.
At high combustion temperatures nitrogen oxides (NOx) are produced in the piston engine cylinder and are conducted with the exhaust gases into the ambient air. Due to the detrimental effects of nitrogen oxide emissions on the environment it is therefore an aim to minimize these emissions.
It is known that introducing water into the combustion process with combustion air reduces the production of nitrogen oxides. This phenomenon is, among other things, based on the cooling effect of the water.
Adding water to the combustion air before the air is introduced into the cylinder is technically less complicated than direct injection of water into the cylinder because the cylinder is at high pressure. To reach a sufficiently high humidity level requires, however, plenty of water. As regards the durability of engine structures and the control of the combustion process, it would be advantageous to remove the non-evaporated water before combustion air is fed into the engine cylinder, as the water fed in this manner is typically in the form of relatively large droplets.
The present invention may be used to provide an air supply arrangement minimizing prior art problems. Especially the present invention may be used to provide an air supply arrangement, by which the humidification of the combustion air is performed advantageously and at the same time effectively.